Fix Error 500 when repositories contain annotated tags pointing to blobs

Closes #27228

See merge request !8800

Make notification_service spec DRYer by making some tests reusable

See merge request !7794

Don't override Ci::Build#user when presenting a build

Closes #26943

See merge request !8668

Document "No gems fetched from git repositories" policy [ci skip]

See merge request !8818

Use `:empty_project` where possible in model specs

See merge request !8832

Use `:empty_project` where possible in request specs

See merge request !8833

Added PHP & NPM samples for Gitlab CI

See merge request !6199

fix depr. warning; use `Devise::Test::ControllerHelpers`

Closes #26942

See merge request !8812

Remove unused js response from refs controller

Closes #27211

See merge request !8828

Add caching of droplab ajax requests

Closes #26844

See merge request !8725

Revert filter-assigned-to-me

Closes #27176

See merge request !8785

fixed small mini pipeline graph line glitch

Closes #27277

See merge request !8804

Fix /explore sorting (trending)

Closes #27044

See merge request !8792

Prevent form to be submitted twice

Closes #27220

See merge request !8825

Fix filtered search so that labels selected from discussion notes display correctly

Closes #27124

See merge request !8756

Merge branch '27254-clicking-line-anchor-multiple-times-causes-scroll-position-to-over-correct' into 'master'

Resolve "Clicking line anchor multiple times causes scroll position to over-correct"

Closes #27254

See merge request !8791

Change repository storage paths location for clarity

See merge request !8757

In repositories such as https://github.com/git/git.git, annotated tags can
point to blobs, not necessarily to commits. `Repository` attempts to
return the tags in the order of the commit date, but if a commit is not
available the previous implementation would error due to a `nil` target.
This change modifies the code to use the current time if a commit
is not associated with the given tag.

Closes #27228

Make sure TraceReader uses Encoding.default_external

Closes #27052

See merge request !8801

Fix https://gitlab.com/gitlab-org/gitlab-ce/issues/27044

Simplify wording in "adding an image" docs

See merge request !8819

Update repository check documentation

See merge request !8815

Fixed flexbox and wrap issues

See merge request !8745

Update two_factor_authentication.md

See merge request !8814

Added hint about the execution order of before_script and artifact restoration.

See merge request !8811

Add a system hook for when a project is updated.

See merge request !5711